Well seeing as you've resurrected it ......
The ATC units in question may be relatively small but I would doubt that they are that easy to run if you're an accountant.
It often surprises me how little understanding people who haven't spent twenty odd years in front of a radar have of how ATC works.
Then again, I probably wouldn't be much cop as an accountant.
But taking my tongue out of my cheek, ATC is a complex system and you need professionals who know what they're doing to manage it. And believe it or not, I suspect Serco are better than many in this respect.